1 /* hvapi.c: Hypervisor API management.
2 *
3 * Copyright (C) 2007 David S. Miller <davem@davemloft.net>
4 */
5 #include <linux/kernel.h>
6 #include <linux/export.h>
7 #include <linux/init.h>
8
9 #include <asm/hypervisor.h>
10 #include <asm/oplib.h>
11
12 /* If the hypervisor indicates that the API setting
13 * calls are unsupported, by returning HV_EBADTRAP or
14 * HV_ENOTSUPPORTED, we assume that API groups with the
15 * PRE_API flag set are major 1 minor 0.
16 */
17 struct api_info {
18 unsigned long group;
19 unsigned long major;
20 unsigned long minor;
21 unsigned int refcnt;
22 unsigned int flags;
23 #define FLAG_PRE_API 0x00000001
24 };
25
26 static struct api_info api_table[] = {
27 { .group = HV_GRP_SUN4V, .flags = FLAG_PRE_API },
28 { .group = HV_GRP_CORE, .flags = FLAG_PRE_API },
29 { .group = HV_GRP_INTR, },
30 { .group = HV_GRP_SOFT_STATE, },
31 { .group = HV_GRP_TM, },
32 { .group = HV_GRP_PCI, .flags = FLAG_PRE_API },
33 { .group = HV_GRP_LDOM, },
34 { .group = HV_GRP_SVC_CHAN, .flags = FLAG_PRE_API },
35 { .group = HV_GRP_NCS, .flags = FLAG_PRE_API },
36 { .group = HV_GRP_RNG, },
37 { .group = HV_GRP_PBOOT, },
38 { .group = HV_GRP_TPM, },
39 { .group = HV_GRP_SDIO, },
40 { .group = HV_GRP_SDIO_ERR, },
41 { .group = HV_GRP_REBOOT_DATA, },
42 { .group = HV_GRP_NIAG_PERF, .flags = FLAG_PRE_API },
43 { .group = HV_GRP_FIRE_PERF, },
44 { .group = HV_GRP_N2_CPU, },
45 { .group = HV_GRP_NIU, },
46 { .group = HV_GRP_VF_CPU, },
47 { .group = HV_GRP_KT_CPU, },
48 { .group = HV_GRP_VT_CPU, },
49 { .group = HV_GRP_T5_CPU, },
50 { .group = HV_GRP_DIAG, .flags = FLAG_PRE_API },
51 { .group = HV_GRP_M7_PERF, },
52 };
53
54 static DEFINE_SPINLOCK(hvapi_lock);
55
__get_info(unsigned long group)56 static struct api_info *__get_info(unsigned long group)
57 {
58 int i;
59
60 for (i = 0; i < ARRAY_SIZE(api_table); i++) {
61 if (api_table[i].group == group)
62 return &api_table[i];
63 }
64 return NULL;
65 }
66
__get_ref(struct api_info * p)67 static void __get_ref(struct api_info *p)
68 {
69 p->refcnt++;
70 }
71
__put_ref(struct api_info * p)72 static void __put_ref(struct api_info *p)
73 {
74 if (--p->refcnt == 0) {
75 unsigned long ignore;
76
77 sun4v_set_version(p->group, 0, 0, &ignore);
78 p->major = p->minor = 0;
79 }
80 }
81
82 /* Register a hypervisor API specification. It indicates the
83 * API group and desired major+minor.
84 *
85 * If an existing API registration exists '0' (success) will
86 * be returned if it is compatible with the one being registered.
87 * Otherwise a negative error code will be returned.
88 *
89 * Otherwise an attempt will be made to negotiate the requested
90 * API group/major/minor with the hypervisor, and errors returned
91 * if that does not succeed.
92 */
sun4v_hvapi_register(unsigned long group,unsigned long major,unsigned long * minor)93 int sun4v_hvapi_register(unsigned long group, unsigned long major,
94 unsigned long *minor)
95 {
96 struct api_info *p;
97 unsigned long flags;
98 int ret;
99
100 spin_lock_irqsave(&hvapi_lock, flags);
101 p = __get_info(group);
102 ret = -EINVAL;
103 if (p) {
104 if (p->refcnt) {
105 ret = -EINVAL;
106 if (p->major == major) {
107 *minor = p->minor;
108 ret = 0;
109 }
110 } else {
111 unsigned long actual_minor;
112 unsigned long hv_ret;
113
114 hv_ret = sun4v_set_version(group, major, *minor,
115 &actual_minor);
116 ret = -EINVAL;
117 if (hv_ret == HV_EOK) {
118 *minor = actual_minor;
119 p->major = major;
120 p->minor = actual_minor;
121 ret = 0;
122 } else if (hv_ret == HV_EBADTRAP ||
123 hv_ret == HV_ENOTSUPPORTED) {
124 if (p->flags & FLAG_PRE_API) {
125 if (major == 1) {
126 p->major = 1;
127 p->minor = 0;
128 *minor = 0;
129 ret = 0;
130 }
131 }
132 }
133 }
134
135 if (ret == 0)
136 __get_ref(p);
137 }
138 spin_unlock_irqrestore(&hvapi_lock, flags);
139
140 return ret;
141 }
142 EXPORT_SYMBOL(sun4v_hvapi_register);
143
sun4v_hvapi_unregister(unsigned long group)144 void sun4v_hvapi_unregister(unsigned long group)
145 {
146 struct api_info *p;
147 unsigned long flags;
148
149 spin_lock_irqsave(&hvapi_lock, flags);
150 p = __get_info(group);
151 if (p)
152 __put_ref(p);
153 spin_unlock_irqrestore(&hvapi_lock, flags);
154 }
155 EXPORT_SYMBOL(sun4v_hvapi_unregister);
156
sun4v_hvapi_get(unsigned long group,unsigned long * major,unsigned long * minor)157 int sun4v_hvapi_get(unsigned long group,
158 unsigned long *major,
159 unsigned long *minor)
160 {
161 struct api_info *p;
162 unsigned long flags;
163 int ret;
164
165 spin_lock_irqsave(&hvapi_lock, flags);
166 ret = -EINVAL;
167 p = __get_info(group);
168 if (p && p->refcnt) {
169 *major = p->major;
170 *minor = p->minor;
171 ret = 0;
172 }
173 spin_unlock_irqrestore(&hvapi_lock, flags);
174
175 return ret;
176 }
177 EXPORT_SYMBOL(sun4v_hvapi_get);
178
sun4v_hvapi_init(void)179 void __init sun4v_hvapi_init(void)
180 {
181 unsigned long group, major, minor;
182
183 group = HV_GRP_SUN4V;
184 major = 1;
185 minor = 0;
186 if (sun4v_hvapi_register(group, major, &minor))
187 goto bad;
188
189 group = HV_GRP_CORE;
190 major = 1;
191 minor = 1;
192 if (sun4v_hvapi_register(group, major, &minor))
193 goto bad;
194
195 return;
196
197 bad:
198 prom_printf("HVAPI: Cannot register API group "
199 "%lx with major(%lu) minor(%lu)\n",
200 group, major, minor);
201 prom_halt();
202 }
203